gyro's stall

[marcox6]

I, my name’s Marco Cilia, I’m a engineering’s student of Catania’s University (Italy).
I make studies about gyroplane, precisely I study a gyroplane that have a weight of 570 kg, it is a tandem and have a engine of 82 kw.
In this first part of my studies I’m trying to determine the minimum forward speed in level flight and I have some difficult because I don’t know some values.
My question are:
1- Do you know approximately the limit value of angle between rotor’s vertical and forward speed? Infact I know that the best efficiency of rotor is for angle of 90 degrees between rotor’s vertical and forward speed, I would know the limit value of this angle before the rotor’s stall.
2- Do you know if exist models of gessow graph for short forward speed?
3- Do you have some information of drag coefficient’s trend when rotor’s blade are near the stall’s angle? I know that drag coefficient increases, but how? In which way?

I hope that I explain well and thanks for your kind attention, every information that you give me will be very important!
Good bye
Marco

[C. Beaty]

Marco, I don’t understand your questions. Rotors stall when the forward speed is too high rather than too low.

Go to the NACA site and type: Autogiro in the search window.

http://naca.larc.nasa.gov/

One of the papers provides experimentally determined stall plots for a gyro at various ratios of rotor peripheral speed to forward speed.